Photocurable, biodegradable liquid copolymers, which undergo liquid-to-gel transformation upon ultraviolet (UV) light irradiation, may find versatile biomaterial applications. A multifunctionally derivatized liquid prepolymer that is oligo(2-hydroxyl methacrylate) grafted with oligo(epsilon-caprolactone) and subsequently end-capped with a photodimerizable group, coumarin, at the terminal ends of the side chains, was prepared. UV irradiation produced a cross-linked solid.